1. Field of the Invention
The field of the invention is that of 3D or STEREOSCOPIC television systems. The invention is more particularly concerned with a new method of processing and transmitting sequences of STEREOSCOPIC images on a data transmission link enabling reconstitution at the receiving end of either a compatible image for a conventional television or a stereoscopic image for a stereoscopic television.
2. Description of the Prior Art
The object of a stereoscopic television system is to achieve on a small screen (small in comparison with a cinema screen) the sensation of three dimensions, i.e. to enable the viewer to perceive the relative distance effect of observed points in the real scene.
The invention integrates into the existing environment of stereoscopic television systems a nd complies with the specific provisions of the "MAC" (Multiplexed Analog Component) transmission standard used for direct broadcasting satellites.
There are already known methods of transmitting sequences of images on a transmission link comprising an analog video channel and an associated "MAC" type digital channel. The actual scene observed is scanned by two synchronized cameras producing a righthand view and a lefthand view.
In the known methods of transmitting sequences of images the analog video channel of the transmission link transmits sequences of images which always corresponds to the same view (the righthand or lefthand view) and the associated digital channel transmits additional data in the form of a vector map making it possible to reconstruct the non-transmitted view from the transmitted view locally, in the stereoscopic television, to produce the 3D display.
This process favors the compatible image, so that a conventional television can easily ignore the additional data transmitted and reconstitute the sequences of images corresponding to one of the views without degrading the resulting non-3D image.
A major disadvantage of these methods is that the stereoscopic image obtained on a stereoscopic television using this information is strongly degraded, especially in "non-predictable" areas, for example if a side of an object visible in one view is not visible in the other view. What is more, these defects are accentuated if the vector map is insufficiently precise or is susceptible to transmission errors.
In the present state of the art, there is no remedy for these problems and there are no data processing methods able to eliminate these critical cases or at least make them less obvious in the resulting stereoscopic image.
Consequently, an object of the invention is a new method of processing and transmitting stereoscopic images on a link comprising an analog video channel associated with a digital channel enabling reconstitution of a stereoscopic image of sufficient quality without degrading the compatible image.
Another object of the invention is a new method of processing and transmitting stereoscopic images adapting itself to the local overall content of the stereoscopic images and to their space-time activity for simultaneous or alternate mode display of stereoscopic views.